Working on my daughters 82 Jimmy with a 350/350 combo. On the trans there are two wire connectors, one on the drivers side and one on the pass side. I figure one's for backup/neutral. What's the other one for?
Are you sure it is a 350?
A Th350 just has a detent cable and a vacume line going to it.
The back up /safty nuetral switch is on the steering column.
A TH 400 has an electric kick down on the drivers side.
Not sure about a 700R4.